Drilling the deep:
in search of a new energy source
„Burning ice“ could solve the energy crisis; but environmentalists warn of potential dangers.
At the end of January 2013, the drill ship Chikyu left Shimizu harbour in Shizuoka prefecture and headed southwest towards Cape Omaezaki. After weeks of preparation, it was on a mission – an experiment that some hoped could be the first step to a solution for Japan’s energy crisis.
In the early morning of 12 March, several pumps on the ship went into action, dropping the pressure in a drill hole some 1,000 meters under the sea and another 300 meters under the sea bed. Hours later, the researchers were rewarded for their efforts when flames shot out of the flare head on the Chikyu: for the first time in history they had successfully extracted gas from a methane hydrate layer, a thick sorbet-like substance in the sea bed.
In six days, they retrieved 120,000 cubic metres of gas, far more than expected, before sand eventually choked the machines and the experiment came to a halt. “The next level of methane hydrate research has been reached”, says specialist Professor Gerhard Bohrmann of the Center for Marine Environmental Sciences (Marum) in Bremen, lauding the efforts of his Japanese colleagues.
It was a great success for Japan, which has spent far more money than any other country on methane hydrate research. To diversify its energy mix and become more energy independent, Japan has been looking for years to find a home-grown solution. Since the nuclear disaster in Fukushima in 2011, efforts have increased to find alternatives to the costly energy imports that weigh heavily on its trade balance. The supporters of “frozen natural gas,” or “burning ice,” as methane hydrate is sometimes called, brush aside the fact that its exploration is technically challenging, time consuming and prohibitively expensive. They are enticed by the perspective that it could possibly satisfy Japan’s energy needs for the next century.
Marine scientists are fascinated by methane hydrate, too, but as a part of their basic research into the oceans to discover how its exploration would affect the eco system of the deep sea. Environmentalists, however, criticize the lack of sustainability and point out possible negative effects on the environment.
Elusive source of energy
“It looks like a McShake,” jokes Yuji Morita, Senior Research Fellow at the Institute of Energy Economics (IEE) in Tokyo and member of the government commission for methane hydrate, when he’s asked to explain what Japan’s energy dreams are made of. Methane hydrate only comes into existence at low temperatures of 4 degrees Celsius or less, and between 20 and 40 bar pressure. Under such circumstances the gas is trapped inside a cage of water molecules that surround the gas-filled core and form an ice-like structure.
It’s the reason why 80 to 90 per cent of worldwide methane hydrate reservoirs can only be found in the “stability zone” between 500 and 2000 metres under the mud layer of the sea bed, and a little closer to the surface in the polar sea. The rest is thought to be located in the eternally frozen ground of Siberia or Alaska.
To be able to use its energy potential, though,wp_re the gas has to be extracted on site from its icy shell. Hot water, gas or even methanol, an antifreeze agent, can be used to melt the crystal cages. However, the most promising method appears to be the one applied in the Japanese trial, lowering the pressure so that it becomes instable, thereby setting free the natural gas inside.
Methane, a colourless and odourless gas, is created through the degradation process of organic material like plankton that has sunk to the sea bed. As the gas is very light, it usually rises up from between the sediments deep inside the ocean ground until it gets trapped in the stability zone. Fishermen are sometimes surprised to find their nets floating towards the ocean surface after accidentally releasing methane hydrate from its cool grave.
Vast methane hydrate reservoirs estimated
Due to its elusive nature, methane hydrate remained undiscovered for a long time; in fact, research has only intensified since the turn of the millennium. Scientists use data from drillings and numerical models based on decay rates of plankton, but are divided about how much might be hidden underground: Professor Klaus Wallmann of the German GEOMAR Helmholtz Centre for Ocean Research Kiel thinks that between 1000 to 5000 gigatons of organic carbon might lie in gas hydrate layers, others estimate 500,000 gigatons. Even conservative estimates are much higher than the reserves of coal, natural gas and oil put together. How much of that can be reached is a different kettle of fish.
Excitement about the potential new energy source is high in Japan, China, Taiwan, Vietnam, India and South Korea, and all have invested a lot of money in its research. India is thought to possess its biggest reservoirs though, according to Bohrmann, “the icy mass might not be homogenous and concentrated enough.” After figuratively and literally digging through murky mud for a long time, researchers have found that sandy sediment consisting of sand of a certain pore size is particularly suited for extraction. Luckily for Japan, there are many such reservoirs nearby. The governmental energy organization Japan Oil, Gas and Metals National Corporation (JOGMEC) thinks that about one-tenth of the methane hydrate around Japan is located near Cape Omaezaki alone.
Global warming possible threat to reservoirs
Though European countries are relying on Russian gas fields for the coming decades, they also have intensified their methane hydrate research. Marum researcher Bohrmann explains: “70 per cent of the surface of our globe consists of ocean, and there is so much we still need to know about it.” Basic researchers like him are trying to find out how the exploration of methane hydrate, as well as oil, affects the eco system of the deep sea. They also want to prove what most scientists believe, but have yet to confirm: That methane hydrate stabilizes the continental slopes that form the border between the shelves and the deep sea.
Research is also being conducted on the effects of global warming on methane hydrate reservoirs and the stability of continental slopes. If too much of the methane hydrate layer dissolves, it could lead to mud slides and even tsunami. And while scientists consider this scenario unlikely, it is not altogether impossible. In the “Storegga Slide” 8000 years ago, underwater landslides near the Norwegian coast triggered mega waves that wreaked havoc across Northern Europe. To reduce such risks, scientists recommend that, prior to any exploration, geotechnical tests be conducted and explorations be done only in marginally inclined areas.
Another potentially damaging effect of warming ocean temperatures is if the methane gas rises up from the depths and into the atmosphere. Methane is a greenhouse gas 30 times more powerful than carbon dioxide, and would do extensive damage to the ozone layer.
For these and other reasons, environmentalists are sceptical. “Considering our limited carbon dioxide budget – why develop something completely new?” asks Greenpeace Japan energy campaigner Hisayo Takada. She argues that it would only prolong the dependence on fossil fuels, and that resources currently spent on methane hydrate exploration would be better used to further develop already existing technologies and improve energy efficiency.
Another decade until commercialization
If such counterarguments are considered at all by the Japanese government, then they are shunted aside. Japan wants to finish developing a suitable technology by 2018. Profitability would be reached if they managed to draw out 100,000 cubic metres a day, five times more than in the 2013 test, Wallmann estimates.
The next step would be commercialisation, says Morita, with the help of private companies. Mitsui Engineering and Shipbuilding, which was involved in the 2013 production test, has already declared its intentions to participate.
However, Morita believes that another 10 to 15 years will pass until commercial extraction is feasible, as the technology must first be improved and the costs lowered significantly. Just to hire a drilling ship for one day sets the government back 50 million yen, he says; others say it costs twice as much.
Greenpeace Japan campaigner Takada says, “We don’t have much time left!” She disagrees with the idea that methane hydrate could be suitable to make the transition from nuclear to renewable energy go more smoothly.
“Golden Age” could help stop climate change
Wallmann, however, supports the continued efforts to try and explore methane hydrate, and predicts a Golden Age of Gas. “In the coming 20 to 30 years, a big part of energy in Asia will be generated from gas hydrates,” he says. The Japanese government seems to agree. In its latest energy plan it reserved generous funds for methane hydrate research – to be used for further data analyses from the previous test and for explorations in more shallow areas like the Japan Sea.
Many basic research scientists currently pin their hopes on a German project called “Sugar,” which is being held close to the South Korean coast this year. The project aims to discover if carbon dioxide, a side-product of energy generation in thermal power plants, could be liquefied and then injected into the methane hydrate reservoirs deep under the deep sea bed. There, carbon dioxide would be converted into the more stable carbon dioxide hydrate, from which methane can be extracted, Bohrmann explains.
If successful, the “burning ice” from the deep sea would not only satisfy energy needs, but also help stop climate change. Bohrmann is excited about the upcoming experiment: “A cycle is created: We get methane and get rid of carbon dioxide.”